U.S. Pat. No. 5,557,990 describes a battery-operated screwdriver having an electric drive motor, which drives a tool holder for holding a tool. The battery-operated screwdriver has a push-start mechanism for switching on the drive motor automatically as soon as the tool held in the tool holder is placed with pressure on the screw to be screwed in or unscrewed and the tool holder is moved axially backward into the housing. During this process, a radially projecting actuating element is moved axially by the tool holder and pressed against a microswitch, which switches the electric motor on and off.
The tool holder is urged into its initial position by the force of a spring element, with the result that the tool holder returns to its initial position as soon as the screwdriver is removed from the screw.